The chance to time-travel and undo a great literary injustice lies before you. For in 1970, the rules of the Booker Prize were changed so as to acclaim only the novels of the previous year.

However, the rule change occurred at such a time and in such a manner as to exclude a number of recently published novels.

One of those was JG Farrell's truly great Troubles, a towering masterpiece of fiction which, as a study of the twilight of empire over Ireland, has never been equalled.

The organisers of the Booker Prize have now opened up the vaults and are allowing the plain people of the world to vote for what should have been the winner in the great missing year.

This is my simple plea: make it Troubles. You can vote for it at www.themanbookerprize.com/news/vote and so ensure posthumously that one of the greatest Irish novels of the 20th century is finally given the public accolade that it truly deserves.

I'm not actually insisting that you read the book before voting: certainly not. For one would gather from many recent Booker winners that the judges hadn't read a word of them.

Indeed, if Troubles has a literary vice, it is that it is the complete opposite of such mud. It is immensely readable, has an exquisite plot with wonderful characters and all in an electrifying setting - Ireland of 1919-21. And it is, of course, beautifully written. These are themselves disqualifications for most literary prizes.

He ventured where curiously few have gone. The Troubles have proved to be either an unexplored, or an unprofitable theme for art.

Indeed, perhaps it was not coincidental that, at the same time that Jim Farrell was writing his novel, David Lean was making his least successful film, Ryan's Daughter, on just the same topic. The two works even contained a similarly neutral character who serves as both a witness and a catalyst to the events around him, namely a shell-shocked British Army officer.

This cipher is not a hero in either work, merely a device around whom the narrative is created, the anchor-line that enables the kite to fly.

In the strangely intuitive way of artists, both Lean and Farrell were addressing a historic theme that 40 years ago was just about to revisit Ireland: republican political violence.

And for Lean's film, no audience anywhere in the world was interested in such a subject. His more recent great works had been big screen-affairs: Laurence of Arabia, Dr Zhivago, Bridge Over the River Kwai. Ryan's Daughter was Lean's greatest flop.

Jim Farrell's novel, set in the doomed unionist fortress of Hotel Majestic, in a muddy hellhole called Kilnalough some time around 1920, could never have been translated into cinema. But it was nonetheless expressed brilliantly in Michael Colgan's strangely forgotten television adaptation of 1986.

This should properly have been hailed as one of the key television dramas of the decade. Instead - perhaps propelled into obscurity by its very subject matter - it is a largely forgotten museum piece. The fate of the television series merely echoes the popular fate of the novel upon which it was set, in spite of the splendid efforts of Farrell's tireless biographer and intellectual cheerleader, Lavinia Greacen. For Ireland's tiresome wars - either 1916-22 or 1969-1996 - seem to be largely unpropitious compost in which to nourish literary fiction.

Yet Troubles uniquely achieves all this: triumphantly, compellingly and most of all, humorously. Furthermore - unlike so many of our wretchedly lazy historians, who have never come close to capturing the horror of the period - Jim Farrell closely studied the newspapers of the time. He then used excerpts from them to provide a sobering backdrop to his own unfolding narrative, as lawlessness spread across the land.

No finer work has ever been written about this transitional period in Irish history: it remains a landmark in 20th-century Irish literature, and one that deserves to win the one and only great retrospective Booker.

Indeed, Troubles could properly be said to be one of few great post-independence, 20th-century Irish novels. Go online and vote for it, and through the internet, exponentially canvas everyone that you and they know: once again, www.themanbookerprize.com/news/vote.

For the first and only time in your life, you can cast your vote, 40 years in the past.